<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
		
	</head>
	<body>
		<canvas id="myCanvas" width="200" height="200"
      >
       </canvas>
	</body>
	
	<script type="text/javascript">
			
			var canvasID = document.getElementById("myCanvas");

              var canvas = canvasID.getContext("2d");

              //画圆方法

              function drawArc(id)

              {

                     canvas.beginPath();

                     canvas.lineWidth = 5;

                     //canvas.fillStyle = "#00f";

                     canvas.strokeStyle = "red";

                     canvas.arc(100, 100, 50, 0, 360, false);

                     //canvas.fill();

                     canvas.stroke();

                     canvas.closePath();

              }

              drawArc("myCanvas");
			
		</script>
</html>
